FIRE ECOLOGY
SPECIES: Cupressus arizonica | Arizona Cypress 



FIRE ECOLOGY OR ADAPTATIONS : 
Arizona cypress is the least fire-tolerant of all trees and shrubs in
the Arizona chaparral zone [69].

The serotinous cones of Arizona cypress persist on the tree for years.
When opened by the heat of a fire, the seeds fall on the exposed mineral
soil, producing thickets of seedlings [68].

Fire history:  Fire regimes in Arizona cypress communities vary greatly
in frequency and severity, and are difficult to determine
dendrochronologically because Arizona cypress tends to produce false
annual rings.  In Arizona chaparral habitats adjacent to Arizona cypress
stands, both wildfires and prescribed fires are frequent [11].  Swetnam
and others [57] determined that the fire history of Chirichua National
Monument for the past 300 years consisted of large surface fires that
burned most or all of Rhyolite canyon at 9- to 22-year intervals.  This
canyon consists of mixed conifer forests and oak woodlands.  Relict
conifer forests dominated by Arizona cypress occur on canyon bottoms at
low to middle elevations [52].  The community in Rhyolite Canyon was
comparatively isolated from fires occurring in the surrounding community
types [43].  In this area, the fire season occurs in late spring and
early summer, during the hot, dry weather that occurs before the summer
rains [57].

Marshall [37] noted a difference in physiognomy between the pine-oak
woodlands in Mexico, where fires are not suppressed, and those in the
United States, where fire suppression is sophisticated and efficient.
He described open woodlands with grassy understories in Mexico; in the
United States, comparable woodlands are stunted, with heavy fuel
accumulations and little grass.  Fires that do occur in these woodlands
tend to be severe and kill most of the understory and overstory plants.

A well-developed population of Arizona cypress occurs in Boot Canyon, in
the Chisos Mountains of Texas (Big Bend National Park).  The fire
history here was also difficult to determine.  Moir [39] estimated that
there had been at least 10 fires between 1770 and 1940, at intervals
from 9 to 60 or more years. He suspected that he had substantially
underestimated the number of fires, and that many of the fires were
low-intensity surface fires that left no scar records.

Vogl and others [66] stated that Piute cypress communities occurring
within pinyon-juniper woodlands are probably burned less frequently than
cypress groves within chaparral.  The southern California varieties of
cypress occur in areas that have more frequent fires and have more
prolonged summer drought [65].  Such frequent fires as occur in
chaparral could destroy cypress groves completely by eliminating young
trees before they reached cone-producing age.  In this area, the
majority of cypress fires occur in the fall [1].  Strong winds and low
humidities commonly accompany or follow these fires [26].  This ensures
maximum cone opening; ejection of seeds from the suspended, opened
cones; and widespread dispersal [65].


POSTFIRE REGENERATION STRATEGY : 
   Tree without adventitious-bud root crown
   Crown residual colonizer (on-site, initial community)

Related categories for Species: Cupressus arizonica | Arizona Cypress